![](http://datasheet.mmic.net.cn/Exar-Corporation/XRT94L33IB-L_datasheet_100163/XRT94L33IB-L_145.png)
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XRT94L33
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
Rev.1.2.0.
145
1.5
AN OVERVIEW OF POSSIBLE CONFIGURATION OPTIONS IN THE XRT94L33
The XRT94L33 can be configured to function a wide variety of operating modes.
This section briefly
summarizes and describes the procedure that one should employ in order to configure the XRT94L33 into
each of these modes.
In all, the XRT94L33 can be configured to function in any of the following modes.
1 Channel STS-3c and up to 2 Channel DS3/E3 ATM UNI/PPP Mode
1-Channel STS-3 (e.g., 3 Channels of ATM UNI/PPP over STS-1, which is in-turn is mapped into STS-3)
Mode
1-Channel STS-3 (e.g., 3 Channels of ATM UNI/PPP over DS3/E3, which is in-turn, mapped into STS-3)
Mode
Each of these operating modes is described below.
1.5.1
1-CHANNEL STS-3C AND UP TO 2 CHANNELS DS3/E3 ATM UNI/PPP MODE
If the user configures the XRT94L33 to operate in this mode, then the XRT94L33 will function as an ATM
UNI/PPP device that supports ATM cell or PPP packet transmission and reception over one STS-3c channel
and possibly as many as two additional DS3/E3 channels, in parallel. Since the UTOPIA and POS-PHY
interfaces, within the XRT94L33 support Multi-PHY Operation, the ATM Layer Processor will have no problem
writing ATM Cell/PPP Packet data into and reading ATM Cell/PPP Packet data from the UTOPIA/POS-PHY
Interface.
Figure 8 presents the functional block diagram of the XRT94L33, if it is configured to operate in this
mode.
Transmit
UTOPIA
Interface
Block
Transmit
UTOPIA
Interface
Block
Receive
UTOPIA/
Interface
Block
Receive
UTOPIA/
Interface
Block
Transmit
ATM
Cell Processor
Block
Transmit
ATM
Cell Processor
Block
Receive
ATM
Cell Processor
Block
Receive
ATM
Cell Processor
Block
Transmit
PPP
Processor
Block
Transmit
PPP
Processor
Block
Receive
PPP
Processor
Block
Receive
PPP
Processor
Block
Receive
STS-3
TOH
Processor
Block
Receive
STS-3
TOH
Processor
Block
Transmit
STS-3
TOH
Processor
Block
Transmit
STS-3
TOH
Processor
Block
Receive
STS-3c
POH
Processor
Block
Receive
STS-3c
POH
Processor
Block
Transmit
STS-3c
POH
Processor
Block
Transmit
STS-3c
POH
Processor
Block
STS-3
Telecom
Bus
Interface
Block
STS-3
Telecom
Bus
Interface
Block
STS-3
PECL
Interface
Block
STS-3
PECL
Interface
Block
STS-3
CDR
Block
STS-3
CDR
Block
XRT94L33 – Channel 0
Transmit
POS-PHY
Interface
Block
Transmit
POS-PHY
Interface
Block
Receive
POS-PHY
Interface
Block
Receive
POS-PHY
Interface
Block
Clock
Synthesizer
Block
Clock
Synthesizer
Block
Microprocessor
Interface
Block
Microprocessor
Interface
Block
SOME NOTES ABOUT THE ABOVE FIGURE
Figure 8 indicates that the XRT94L33 is functioning as a 1-Channel STS-3c ATM UNI/PPP device. The
existence of the two DS3/E3 channels are not depicted in this illustration.
Nonetheless, whenever the
XRT94L33 is operating in this mode, these additional DS3/E3 channels are available for the transmission of
ATM cell or PPP packet.